Jim, I was just looking at Atkins website and got some interesting information. The page of interest is:

http://americanrotaryengine.com/id10.html

and it contains the quote

"The 55 tooth internal spur ring gear raises propeller shaft almost 2 inches for improved propeller clearance, resulting in an identical propeller centerline as Lycoming installations and..."

At this point, I don't know where my engine sits, compared to the Lycoming.  The plans say to put the engine's mounting face on the aircraft centerline vertically, and provide 1.5degrees upthrust.  Then the engine's rear mounting surface's centerline is moved left 1/4", to give 2/3rd degrees right thrust.

Right or wrong, I used the center of the firewall end of the eccentric shaft as the 'mounting surface centerline'.  Made it level with the aircraft centerline and 1/4" to the left.  Since the PSRU shaft is concentric with the eccentric shaft, I kept it on the horizontal centerline and moved it up 5/8" from the vertical.  From the above statement, I may have just shortened my prop by 2".

Well, I was wanting to have a go at building a 4-blader anyhow.